Experimental and numerical study on a cavity-swirler-based combustion strategy for advanced gas turbine engine

Abstract

A cavity-swirler-based combustor has been found to possess the capability of achieving robust stability, high combustion efficiency, low emissions, and a short flame length. However, the effect of cavity air-injection mode on the combustion and emission performances of the cavity-swirler-based combustor was not well understood to date. In this work, numerical and experimental investigations were conducted to analyze the flowfield, combustion efficiency, combustion stability, pollutant emissions, temperature distribution, and flame characteristics of the combustor under two different cavity air-injection modes, namely case-1 and case-2. The air-injection hole of case 1 was designed on the cavity inner-wall, while the air-injection hole of case 2 was designed on the cavity outer-wall. The results indicate that the combustion performance of the combustor is significantly influenced by the air-injection mode, leading to different flow fields within the combustor. Case 1 demonstrates notable advantages in terms of lean blowout limit compared to case 2. However, case 2 achieves a much more uniform distribution of outlet temperature. Higher combustion efficiency was achieved by case-1 under low fuel equivalence conditions, whereas case-2 exhibited greater combustion efficiency under high fuel equivalence conditions. Both case-1 and case-2 displayed distinct combustion zones that were separate from each other.